// -------------------------------------------------
// BlinKit - BlinKit Library
// -------------------------------------------------
//   File Name: BMPImageDecoder.h
// Description: BMPImageDecoder Class
//      Author: Ziming Li
//     Created: 2021-07-31
// -------------------------------------------------
// Copyright (C) 2021 MingYang Software Technology.
// -------------------------------------------------

/*
 * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
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 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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 */

#ifndef BMPImageDecoder_h
#define BMPImageDecoder_h

#include "platform/image-decoders/bmp/BMPImageReader.h"
#include "wtf/OwnPtr.h"

namespace blink {

// This class decodes the BMP image format.
class PLATFORM_EXPORT BMPImageDecoder final : public ImageDecoder {
public:
    BMPImageDecoder(AlphaOption, GammaAndColorProfileOption, size_t maxDecodedBytes);

    // ImageDecoder:
    String filenameExtension() const override { return "bmp"; }
    void onSetData(const std::shared_ptr<SharedBuffer> &) override;
    // CAUTION: setFailed() deletes |m_reader|.  Be careful to avoid
    // accessing deleted memory, especially when calling this from inside
    // BMPImageReader!
    bool setFailed() override;

private:
    // ImageDecoder:
    void decodeSize() override { decode(true); }
    void decode(size_t) override { decode(false); }

    // Decodes the image.  If |onlySize| is true, stops decoding after
    // calculating the image size. If decoding fails but there is no more
    // data coming, sets the "decode failure" flag.
    void decode(bool onlySize);

    // Decodes the image.  If |onlySize| is true, stops decoding after
    // calculating the image size. Returns whether decoding succeeded.
    bool decodeHelper(bool onlySize);

    // Processes the file header at the beginning of the data.  Sets
    // |imgDataOffset| based on the header contents. Returns true if the
    // file header could be decoded.
    bool processFileHeader(size_t& imgDataOffset);

    // An index into |m_data| representing how much we've already decoded.
    // Note that this only tracks data _this_ class decodes; once the
    // BMPImageReader takes over this will not be updated further.
    size_t m_decodedOffset;

    // The reader used to do most of the BMP decoding.
    OwnPtr<BMPImageReader> m_reader;
};

} // namespace blink

#endif
